You asked
Is the 7artisans af 135mm f 1 8 good in low light?
Yes, on paper it's built for low light. The 7Artisans AF 135mm f/1.8 is a fast prime, and f/1.8 gathers far more light than any kit zoom, which matters in dim rooms, indoor events and evening portraits. It's made for full frame and fits Sony E, Nikon Z and L-Mount.
It has no stabilisation, though, so at 135mm you'll want a shutter speed of around 1/135 s or faster when shooting handheld. A camera with in-body stabilisation will help. The sensor sizes guide explains when a full frame body is worth it for low light.
The Viltrox AF 135mm f/1.8 LAB has the same focal length and maximum aperture. I don't have low-light results for either lens, so I can't say which one handles noise and focus better in the dark.
Written by Claude from this site's pages.